Vatican Swiss guards salute as cardinals arrive for a meeting at the Vatican on Monday. / Andrew Medichini, AP

by Eric J. Lyman, Special for USA TODAY

by Eric J. Lyman, Special for USA TODAY

VATICAN CITY - The process of picking a successor to Pope Benedict XVI officially got underway Monday with more than 100 of the electors meeting in "congregations." Vatican officials said the date of the papal conclave will not be set until all the cardinal electors are in town.

Of the 115 cardinals eligible to vote, 103 were in Rome for the pre-conclave meeting in which the cardinals get to know one another better. The Vatican said the cardinals prayed together and talked over coffee.

Twelve more cardinals had yet to arrive. The dean of the College of Cardinals, Cardinal Angelo Sodano, has said a date won't be finalized until all the cardinals are at the Vatican.

Rev. Federico Lombardi, the Vatican spokesman, characterized the talks as "positive, serine, warm, cordial, and constructive." He did not speak about specific topics of discussion.

On Monday each cardinal present took an oath pledging to honor "rigorous secrecy with regard to all matters in any way related to the election of the Roman pontiff." The cardinals also agreed to send pope emeritus Benedict XVI, who resigned Thursday, a message on behalf of the group, the Vatican said.

The meetings are being translated into five languages -- English, French, German, Italian and Spanish -- with the translators sworn to secrecy about what they hear.

Benedict XVI remained at the papal residence at Castel Gandolfo, his temporary retirement home while cardinals pick his successor.

Outside the Vatican, television crews swarmed the red-capped churchmen arriving for meetings.

"A Latin American pope is possible, everything is possible!" said Portuguese Cardinal Jose Saraiva Martins as he entered.

The cardinals discussed procedures for closing the Sistine Chapel to visitors and getting the Vatican hotel cleared out. It was revealed that someone dressed as a bishop and with a staff of fake priests tried unsuccessfully to sneak into the meetings.

Lombardi declined to elaborate, saying only: "All I can say is that everyone seated for the congregation is a real cardinal."

All told, 142 of 207 cardinals -- including those age 80 or older, who cannot vote for the next pope -- participated in the morning meetings.

One cardinal who will not be attending is Scottish Cardinal Keith O'Brien, who admitted Sunday that he was guilty of "inappropriate" relations with priests in the 1980s. Also absent will be Indonesian Cardinal Julius Darmaatmadja, who is too frail to travel.

Lombardi said the structure of the meetings has been designed to allow for ample time for informal discussions. He said at the last conclave, in 2005, when Benedict was selected to succeed John Paul II, such early discussions were essential in determining the leading candidacies for the papacy especially among cardinals working far from Rome and unfamiliar with many of their fellow cardinals.

The meetings are being led by Sodano, the dean; Cardinal Tarcisio Bertone, camerlengo of the Apostolic Camera; and Archbishop Lorenzo Baldisseri, secretary of the Congregation of Bishops. They were joined by three cardinals selected as assistants, one from each order: Cardinal Giovanni Battista Re, Cardinal Crescenzio Sepe, and Cardinal Franc Rode. These assistants will serve for three days each, after which a new group will be selected.

Bertone, Battista Re, and Sepe are among those cardinals who may be leading candidates to become pope.